Current methods of mobile electronic device design create devices that are static, both in terms of functionality and in terms of design. Companies try to solve this problem by producing a wide range of devices having different functionalities and different designs. As a result, users of such devices are forced to make compromises; they lack the ability to customize the functionality and design of their mobile devices to truly meet their needs and preferences. Modular mobile electronic devices may serve to meet user needs and preferences; but for modules to work as part of a modular mobile electronic device, modules must be able to interface with the modular mobile electronic device. Typical modular add-ons to mobile electronic devices suffer from poor interface design; they are often not secure when attached, break easily, and are not designed for repeated connection and disconnection. These qualities make users less inclined to use add-ons, decreasing their value. Thus, there is a need in mobile electronics field to create systems for module interfacing of modular mobile electronic devices. This invention provides such new and useful systems.